Marine & Freshwater Environmental Education
You must be brave enough to pinch the body of the blue crab from behind and lift it upside down (It hurts a lot if they pinch you!).
Male blue crabs have a distinct shape like a pencil – or the Washington Monument – in the center of their bellies. Female blue crabs, on the other hand, have a shape like the Capitol.
http://treadoutdoors.blogspot.com/2012/10/my-husband-gave-me-crabs.html
…It’s Charismatic Microfauna!
Well, yes there’s the sand, but there is also an unrecognized and perhaps even shocking biodiversity that lies not quite below the surface.
Would you believe me if I told you that in a single handful of wet sand you could be holding a community of organisms equaling, if not exceeding, the diversity found in an Amazonian rainforest?
All too often we suffer from a bias of scale, but biodiversity includes all organisms, including the mega-, the micro- and the meiofauna.
So just who are the meiofauna?
They are the smallest animals on earth—some no larger than a grain of sand.
They live in ultra-micro habitats within habitats and make an excellent example of the complexity of ecosystems and the interconnectedness of life.
The meiofauna aren’t a kind of animal, but rather a size-class of animals that live (mostly) in and among aquatic and marine sediments. (Fully 25 animal phyla have representatives in the meiofauna and they boast some of the most unique and strange biological adaptations in the Animal Kingdom.)
Without a microscope and a little curiosity, you’d probably never notice they were there…but you’d certainly notice if they weren’t…
Among the roles meiofaunal animals play in their environment is that of the decomposer. Beaches without a strong meiofaunal component have a distinctive, sulphuric odor of decay.
The meiofauna provide even more proof that there will always be new discoveries to be made in the marine environment—not just for us, but for all of science.
The newest animal groups described have been meiofaunal—three entirely new phyla described in the last 25 years. Exploring the meiofauna opens a whole new world discovery for even the most jaded, know-it-all, marine biologist!
But we’ve only scratched the surface here. Check back often at beachchairscientist.com for more about some of my favorite meiofauna.
By Jim Wharton, Director, Center for School and Public Programs with Mote Marine Laboratory
Photo (c) Rick Hochberg
I have two answers for you here – Mole Crabs or Sand Hoppers.
Mole Crabs:
Unfortunately, not all crabs are as interesting in appearance or function as the great Atlantic Horseshoe Crab, but the mole crab has some merit.
Mole Crabs, or one type of sand fleas thingees, are properly referred to as Emerita analoga. A pretty dignified, but boring sounding Latin name – rather appropriate for the critters too.
Here is why:
Sand Hoppers:
These little guys truly are harmless. Sand hoppers, or the other type of sand flea thingees, are properly referred to as Orchestia. They are most often found in clumps of rotting seaweed – which they eat. They resemble small shrimp and are about a half an inch long and “hop” by using their tails and last three sets of legs.
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Sand is basically the tiny particles eroded from the mountains or rock formation closest to the beach you are standing on as well as some other bits and pieces. The three main ingredients common to all the beaches are: quartz, old shell parts, and decayed materials from the sea and land.
I saw the most interesting image of sand gradients going from really dark to really light as one traveled from Maine to Florida. Which makes sense since the chemical make up of those mountain ranges and the biological life in each of those areas is unique.
Someone did ask me if sand was a natural exfoliates our skins – and the answer is basically, yes. There are a lot of natural exfoliates out there and sand is one – in the sense that it helps to remove dead skin cells, like sponges you see for sale. Maybe not the most comfortable – but, certainly one of the most accessible if you get a burn (once mixed with water – it really cools you off, but looks gross).
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These tiny colorful clams are commonly known as coquina clams.
Did you see them wriggle under the sand? They use a muscled foot to dig a burrow and hide from their enemies: crabs, sea stars, and snails. They can feed themselves with the muscle coming out of the other end, called a siphon. The siphon basically just sucks in the “vitamins” of the sea for the clam to grow on.
Clams grow very fast in the summer and fairly slow in the winter. You can tell the age of a clam by counting the darker rings. The softer rings are the slow growth of winter. Think how your hair grows longer and faster in the summer.
Did you know that colorful coquina clams are the sign of a healthy beach? Check the video posted here!
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It was another great weekend on the beach for my family and everyone had new and exciting Beach Chair Scientist questions. The best part about being a Beach Chair Scientist is clarifying misconceptions, so I am going to start with the question that seemed to garner the most discussion this weekend “What are jellyfish?”.
Jellyfish, contrary to their popular common name, are not fish at all! As a matter of fact, neither are starfish. Popular nicknames to avoid this misconception can be to call them jellies or seastars.
Jellies are basically giant plankton. Plankton is anything (living) that is free-floating. It can be a plant (known as phytoplankton) or an animal (known as zooplankton). Jellies are zooplankton. Floating is easy for them. They are over 90% percent water. People are approximately 70% water. Jellies are in the family Cnidaria (the c is silent). Also in this group are sea anemones and coral.
What do jellies, sea anemones, and coral all have in common?
1. One giant cavity for all digestion
2. Stinging cells (known as nemotacysts)
3. Tentacles
4. Radial symmetry (no matter how you slice it, you will have 2 halves)
Jellies are essentially a giant mouth with intestines surrounded by a skeleton. They have a nerve-net surrounding their transparent skeleton. The nerve-net in some species extends towards the tentacles. Not all jellies have painful toxins in their tentacles.
What do you do if you are infected with a toxin tentacle?
1. Wash with soap and water
2. Apply alcohol, or meat tenderizer and Vaseline
3. Apply ice and contact a doctor
Image (c) pdphoto.org
Do you have another great question? Email info@beachchairscientist.com and just let me know. I can also be reached at Flurl as usual of course.
Actually seaweed is a term given too many different types of marine plants that grow in the ocean and none of them are weeds, in the sense that we would try to get rid up them with a weed killer.
The basic scientific term would really be algae. Algae (Red, brown, or green) are a very large single celled phytoplankton.
Phytoplankton in the world’s oceans is extremely important due to their immense numbers.
Did you know there is more phytoplankton producing oxygen and absorbing the carbon dioxide than there are trees on the land?
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Some might say that the horseshoe crab is quite possibly the scariest looking creature along the shoreline. However, I disagree. There’s actually a sweetheart of an animal underneath that tough, pointy, chitin exoskeleton. I am certain that the horseshoe crab has survived since before the time of the dinosaurs due to its ability to adapt and take in stride all conditions (Darwin’s theory of ‘only the strong survive’ should more aptly be taken as ‘the most adaptable species will prevail‘).
The shells that you may see washed up along the coast line are probably molts. Horseshoe crabs have to shed their exoskeleton just like crustaceans. They grow on average a quarter of their size each time they shed. Females grow to be approximately two feet across and males and a bit smaller (which helps for reproductive reasons).
Another reason that the horseshoe crab is a lot less intimidating than one might think is that the pointy ‘tail’ (telson) is not going to sting you at all. It is what helps the animal turn itself over when the ocean currents flip it a bit. For ten months out of the year horseshoe crabs live in the depths of the ocean floor. They are most often seen coming to the shore in May and June.
Image (c) FreeFoto.com
Please visit the Limulus Love page for more information about the Atlantic horseshoe crab.
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